Overload Vitamins

Beta-Carotene
Recommended daily amount (RDA) not established
Top Limit 600 mg
The risk Smokers (and inhalers of secondhand smoke) beware: When beta-carotene taken in supplement form mixes with cigarette smoke, it changes from an antioxidant that wards off cancer to a harmful pro-oxidant that ups the risk of lung cancer. Get the nutrient through foods like carrots and sweet potatoes rather than pills.

Calcium
RDA 1,000 mg
Top Limit 2,500 mg
The risk Watch out for calcium-fortified Tums or new calcium-fortified chocolates. Too much calcium can lead to kidney stones, calcium deposits in your arteries, and, ironically, weakened bones. That's because an excess of calcium prevents absorption of other nutrients necessary for bone health, such as magnesium, says Mark Woodin, Sc.D., professor of epidemiology and environmental health at Tufts University in Boston.

Iron
RDA 18 mg
Top Limit 45 mg
The risk Studies show that high blood levels of iron (found in meats, spinach, lentils, and soybeans) may be a risk factor for heart disease. Iron also competes with important minerals like copper for absorption in the body, says Roberta Anding, R.D., a spokesperson for the American Dietetic Association.

Vitamin A
RDA 5,000 mg
Top Limit 30,000 mg
The risk Too much vitamin A can cause liver problems, diminished bone density, and birth defects, says Martha Belury, Ph.D., a professor of nutrition at Ohio State University and WH advisor. Since you get the vitamin A you need through foods like milk, eggs, carrots, and peppers, a supplement isn't necessary.

Zinc
RDA 8 mg
Top Limit 40 mg
The risk An overdose of zinc can lead to hair loss, ovarian cysts, and muscle spasms. It isn't hard to max out when some lozenges for cold relief deliver between 46 and 50 milligrams a day, according to ConsumerLab, an independent firm that verifies commercial claims.

This from http://www.womenshealthmag.com/
Basically all of the overload vitamins is bad, just consume enough vitamin and the other mineral.
Don't forget to drink at least 8 glasses of mineral water or it same with 2 liters mineral water and do some exercises.